Spontaneous Detachment of Colloids from Primary Energy Minima by Brownian Diffusion
Date
2016-01-19
Journal Title
Journal ISSN
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Publisher
Public Library of Science (PLOS)
Abstract
The Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy profile has been frequently
used to interpret the mechanisms controlling colloid attachment/detachment and
aggregation/disaggregation behavior. This study highlighted a type of energy profile that is
characterized by a shallow primary energy well (i.e., comparable to the average kinetic
energy of a colloid) at a small separation distance and a monotonic decrease of interaction
energy with separation distance beyond the primary energy well. This energy profile is
present due to variations of height, curvature, and density of discrete physical heterogeneities
on collector surfaces. The energy profile indicates that colloids can be spontaneously
detached from the shallow primary energy well by Brownian diffusion. The spontaneous
detachment from primary minima was unambiguously confirmed by conducting laboratory
column transport experiments involving flow interruptions for two model colloids (polystyrene
latex microspheres) and engineered nanoparticles (fullerene C60 aggregates).
Whereas the spontaneous detachment has been frequently attributed to attachment in
secondary minima in the literature, our study indicates that the detached colloids could
be initially attached at primary minima. Our study further suggests that the spontaneous
disaggregation from primary minima is more significant than spontaneous detachment
because the primary minimum depth between colloid themselves is lower than that
between a colloid and a collector surface.
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Citation
Wang Z, Jin Y, Shen C, Li T, Huang Y, Li B (2016) Spontaneous Detachment of Colloids from Primary Energy Minima by Brownian Diffusion. PLoS ONE 11(1): e0147368. doi:10.1371/journal. pone.0147368